I recently purchased a WE brand M9A1 off of Evike.com and received it 2 days ago, but there's a problem. The outer barrel is sitting off center to the left, throwing my shots off and I have to aim my front sight to the right to compensate. I've taken it apart several times to try and remedy the issue but can't figure it out. If anyone knows or at least has a decent guess as to why this is happening, I'd appreciate the advice.